Fluid pressure device



Feb'.v 15, 1944. i -w; J. ANDRES Erm. 2,341,587

' FLUID PRESSURE DEVICE Filed oct. 9, v1941 .5 Q1 u@ y `(l K "Il V lllll D lN N v A l O @v Y N l, o1 ....g' w@ Y y v L.. a Q N #S se Roy 5.5cuyrct.

Patented Feb. 15, 1944 FLUID PRESSURE DEVICE William J. Andres, Morris, N. Y., and Roy S. Sanford, Waterbury, Conn., assignors to Bendix- Westinghouse Automotive Air Brake Company, Elyria, Ohio, a corporation of Delaware Anoliontlon october 9, 1941, serial No. 414,353

` fol. 121-33) y 11 Claims.

This invention relates to fluid pressure controllingl apparatus and more particularly to a mechanism for remotely controlling the actuationl of a vehicle clutch.

Various types of constructions have heretofore been proposed for remotely controlling the engagement and disengagement of a vehicle clutch, for example, such devices in many cases constituting a fluid motor having a cylinder and a piston, with the piston connected with the clutch throwollt lever in such a manner that variations in fluid pressure in the cylinder serve to control r el engagement and disengagement of the clutch plates. Among the problems presented by previous installations of this type, however, has been that of erratic operation of the clutch lever due to the inherent friction between the peeking used on the piston and the wall of the cylinder, this undesirable friction tending to prevent the actuation of the clutch throwout lever from directly following changes in pressure in the cylinder in response to operation of the control valve therefor. l

It is accordingly an object of the present invention to provide a fluid motor so constituted as to overcome these disadvantages. a

Another object of the invention is to provide a. fluid motor for the remote control of devices to be actuated, so constituted as to provide smooth o and uniform actuation of the ydevices under all conditions.

A further object of the invention is 'to provide, in connection with ailuid motor of the type above `referred to, an arrangement for rendering the motor unusually efficient during one particular portion of the operating range thereof.

Yet another object of the invention is to provide, in a fluid motor, a piston construction so constituted as to substantially minimize the detrimental eilects of the friction inherent between the piston and the Cylinder wall. v

These and other objects and novel features of the invention will appear more flllly hereinafter from. the following detailed description when taken in connection with the accompanying drawing, illustrating one form of the invention. It is to be expressly understood. however, that the drawing is employed for purpose of illustration only and is not Ydesigned as a denition of the limits of the invention, reference being had for this latter purpose to the appended claims.

Referring to the drawing. the single figure therein illustrates the present invention indiagrammatic form, certain parts being shown in section. More particularly, the invention is illusktrated in connection with a friction clutch l, of

the type commonly used on motor vehicles, a driving plate 5 being driven by the vehicle engine, not shown, through the medium of a crankshaft 6, connected thereto, and serving through its frictional engagement therewith to drive a driven plate 1, normally maintained in engagement with the plate 5 by means of spiral springs 8 interposed between the driven plate and a portion of the engine housing 9. f A shaft I0, attached to the driven plate, serves to drive the wheels of the vehicle through any suitable connecting means, not shown, this shaft being slidably mounted and adaptedto be moved axially in one direction or the other by means of a clutch actuating lever l I pivotally mounted on the vehicle frame bymeans of a pivot pin I2 and having a pin I3 adapted to engage a groove Il formed on the shaft ill. It will be readily understood that with theconstruction described, clockwise rotation of the lever ll about the pivot pin I2 will tend to move the shaft Ill to the left with corresponding movement of the plate 1 to the left against the force exerted by the springs 8, this action serving to disengage theA clutch in the well known manner.

of the cylinder for .guiding the piston, a packing cup 23 being clamped between the guide member and the piston in sealing engagement with the wall of the cylinder. As shown, the piston is a formed with a hollowchamber 24 therein, the

left end of the chamber communicating with the interior of the cylinder, through the mediumV of a port 25 provided in the screw 2|, and the right` end of the bore being closed by means of a pressure responsive diaphragm 26 clamped at its outer edge between the right end of the piston body and a cover plate 2l screwed thereto, and clamped at its center to a member 28 by means of a clamping plate 29 screwed thereto. An operating connection between the member 28 and the upper end of the lever Il is accomplished by means of a connecting rod 30 threadedly received at its left end in the member 28 and pivotally connected at its right end with the lever Il by means of a pivot pin 8l. A bore 32 is provided in the plate 21, this bore being slightly larger Asl illustrated, the cylinder of the fluid motor Y l is adapted izo-receive uuid under pressure from a. reservoir 35, through the medium of a conduit 36, an operators control valve 31 and a conduit 38 having a connection with the interior of the cylinder. The control valve 31 is preferably of the well-known self-lapping type and may-be constructed as disclosed in Fig. l of the patent to William J. Andres and Roy S. Sanford, No. 2,133,275, issued Octoberl, 1938. For the purposes of this description, it will be understood that depression of the pedal 39 of the brake valve 31 serves to actuate the valve mechanism to establish a connection between conduits 36 and 38, while release of the pedal of this type, however, considerable clockwise movement of the lever ll is necessary before the force tending to hold the clutch plates together is suiilciently reduced to permit slipping to occur between the plates, and the tension of the spring 34 is accordingly so chosen as to prevent relative movement between the member 28 and the piston. i9 until, this pointv'ofoperation is approachedl' As the pressure theinterior oik the cylinder I6 is increased to this point, however, the pressure acting on the diaphragm 2i as Vconveyed thereto through the port 25 of the screw 2l and through the medium of chamber 24 exerts a force suilicient to' overcome the tension of the spring 34 and to permit corresponding movement of the diaphragm and the attached parts to the right with respect to the piston with the resultant tendency to further actuates the valve mechanism to establish'a connection between conduit 38 and an exhaust'port 40 provided on the control valve.v It will thus be understood that the operator may at all times control the actual pressure in the interior of the uuid motor I5.

In previous clutch control mechanisms, the

` piston has in some cases been directly connected with the clutch'actuating lever, with the result that the inherent friction between the piston packing 23 and the wall of the cylinder has prevented a given change of pressure in the cylinder from resulting in a corresponding change in position of the clutch operating lever li, and consequently of the force holding the clutch plates in engagement The resultant erratic controlA of the pressure exerted on the Vclutch plates,`and consequently of the degree of slip between the plates has been particularly detrimental in the control of s uchclutches with the parts in'such a position a's to cause the clutch plates to be partially 'engaged or about toiully engage, and the present mechanism is particularly designed to provide smooth and uniform operation'when the clutch parts are in this position.

With the parts in theposition shown, it will be understood that the clutchy plates are fully engaged under the actionof the springsv 8,* and that thev lever Il is substantially free from any force tending to rotate it in'either direction about the pivot pin l2, .the piston `,member I9 being provided with a shoulder 4| adapted to rest against a. similar shoulder 42 `formed at the right end of the cylinder I6, and the member 28, connected to the push rod 30 resting against stops 43 formed on the right side of the piston member I9. 'I'hus thespring 34 being under a predetermined tension, tends to forceparts 21 and 28 apart, but undesirable distortion of the diaphragm due to this action is preventedv by the engagement of the left Aside of the member 28 with the stops 43.

Assuming now that the operator is desirous of actuating the mechanism to disengage the clutch, the valve 31 is operated to supply a desired amount of iluid lmder pressure to the interior of the cylinder I6, this pressure acting on the piston I 9 to force the latter to the right, this motion in turn being transmitted to the rod 30 through the medium of stops 43 and plate 28, with resultant clockwise movement of the lever il to disengage the clutch. In clutches gree of fluid pressure is Y in the event the force actuate the push rod 30 to the right and to further reduce the pressure between the plates of the clutch.- Sincevthe diaphragm 26 and its associated parts inherentlyhave Ia very small amount of'friction or movement, in comparison with the frictionbetween the piston cup 23 and the cylinderffwall, it will be apparent that in the event thelpiswn cupinds to sack or bind inl the cylinder'4 whenthe above described dereachedtherein, the dia` phragm will then take up the work of acting as a iluid motor to actuate the clutch lever I|,and exerted on the rod Il through the medium of the diaphragm 26 exceeds the combined 'air pressure force and friction force tending to prevent movement of the piston to the left, the piston will in this case, tend-to move slightly to the lett until a new position ofequilibrium of the forces involved is reached; It will also be understood by those skilled in the art that during this type of operafa newv condition of tion of theiluid pressure l the diaphragm alone may be eiective to actuate the rod 30 through the A* ance shown between the right face of the plate 28 and the left face of the plate 2? even though the piston cup firmly adheres to the cylinder wall without slipping during this particular period of operation. Il', on the other hand," the friction between the cup and the cylinder Wallis overcome during this period of operation 'by an increasein the pressure of fluid in the cylinder, the piston body will move tothe right while a'tfthe same time, relative movement with respect to the body may occurfto establish equilibrium of the parts.

It will be seen fromv the foregoing that the springs 8 normally oppose movement of the piston rod 30 to the right as well as movement of the piston itself,lwhile the spring 34' opposes movementof the rod 30 to the right with respect` to the piston I9, thevtension' of thefspring I4 being carefully chosen with respect to the eilective area of the diaphragm 2,6 as well as vwith respect tothe forces-which must'be employed to actuate the clutch throwouty mechanism.

Diierent combinations of areas of the pressure device above described,

of the diaphragm to the left of the invention.

What is claimed is: 1. The combination with a source of rluid pressure and a device to be actuated, of a iluid motor having a casing 4adapted to receive uid under pressure from said source, a pressure responsive member movably mounted in said casing and responsive to the pressure therein, a second pressure responsive member of greater area carried by the first named pressure responsive member and subjected to the pressure in the casing, means for connecting one of said responsive members with the device to be. actuated and preloaded resilient means interposed between said pressure responsive members for preventing relative movement therebetween when the pressure supplied to said fluid motor is less than a predetermined value.

2. The combination with a source of fluid pressure and a device to be actuated, of a fluid motor comprising a casing adapted to receive said fluid, a bore formed in said piston, means for establishing a connection for uid pressure between said cylinder and bore, means for closing the end of said bore including a pressure responsive member carried by said piston having a greater area and subjected to thepressure of fluid in said bore, means for connecting said pressure responsive member with the device to be actuated, and preloaded resilient means interposed between said pressure responsive member and piston for preventing movement of said presfluid under pressure from said source, a pressure responsive member mounted for movement in said casing and subjected to said fluid pressure, a second uid pressure responsive member of greater area carried by said first named pressure responsive member and subjected to the pressure in said casing, means for connecting one of said pressure responsive members with the device to be actuated, and preloaded resilient means interposed between said pressure responsive members for preventing movement of said second named pressure responsive member relative to said first named pressure responsive member until the pressure in the casing exceeds a predetermined value.

3. The combination with a source of iluid pressure and a device to be actuated, of a fluid motor having a casing adapted to receive uid under pressure from said source, a piston mounted in said casing and subjected to the pressure therein, a pressure responsive member carried by said piston having a greater area and subjected to the pressure in said casing, means for connecting said pressure responsive member with the device to be actuated, and means including a preloaded spring interposed between said piston and pressure responsive member for preventing movement of said pressure responsive member relative to said4 piston until the pressure in said casing exceeds a predetermined value.

4. The combination with a source of iiuid pressure and a device to be actuated, of a fluid motor comprising a cylinder adapted to receive fluid under pressure from said source, a hollow piston slidably mounted in said cylinder, a pressure responsive member carried by said piston having a greater area and closing one end thereof, means for connecting said pressure responsive member with the device to be actuated, means for conducting uid pressure between the cylinder and the interior of said hollow piston and preloaded resilient means interposed between said piston and pressure responsive member for preventing relative movement therebetween when the pressure supplied to said fluid motor is less than a predetermined value.

5. The combination with a source of fluid pressure and a device to be actuated, of a fluid motor for actuating said device including a cylinder adapted to receive fluid under pressure from said source, a piston slidably mounted in said cylinder and subjected to the pressure' of sure responsive member with respect to said piston until the pressure in said bore exceeds a predetermined value.

6. The combination with a source of iiuid pressure and a device to be actuated, of a fluid motor for actuating said device including a cylinder adapted to receive fluid under pressure from said source, a piston slidably mounted in said cylinder and subjected to the pressure therein, apressure responsive member carried by said piston having a greater area and subjected to the pressure in said cylinder, means for eiecting y an operative connection between the pressure responsive member and the device to be actuated,

resilient means for opposing the movement of v said connecting means for actuating said device,

and preloaded resilient means carried by said piston for opposing movement of said pressure responsive member relative thereto.

7. A combination with a source ,of fluid pressure and a device to be actuated, of a fluid motor for actuating said device including a cylinder adapted to receive iiuid under pressure from said source, a pressure responsive member mov-l ably mounted in said cylinder and subjected to the pressure of fluid therein, a second pressure responsive member of greater area carried by said rst named pressure responsive member and subjected to the pressure of fluid in said cylinder, means for eiecting an operative connection between one of said pressureresponsive members and said deviceand preloaded resilient means for opposing movement of said rst and second named pressure responsive means.

8. The combination with a source of fluid pressure and a device to be actuated, of a casing adapted to receive uid under pressure from said source, a pressure responsive member mounted in said casing for movement with respect thereto and subjected to the pressure of fluid therein, a second pressure responsive member of greater area carried bysaid rst named pressure responsive member, mounted for movement with respect thereto, and subjected to the pressure in said casing, means for connecting one of said pressure responsive members with the device to be actuated, and preloaded resilient means'or opposing relative movement of said pressure responsive members in one direction.

9. The combination with .a source of fluid pressure and a device to be actuated, of a cylinder adapted to receive uid under pressure from said source, a piston slidably mounted in said cylinder and subjected to the pressure therein, a chamber formed in said piston and adapted to receive iiuid under pressure from said cylinder, a diaphragm mounted in said chamber and subjected to the pressure therein, means for connecting said diaphragm with the device to be actuated, and resilient means interposed between the piston and diaphragm lfor opposing relative movement therebetween in one direction.

10. The combination with a source of uid pressure and a device to be actuated. ot a casing adapted to receive iiuid under pressure from said source, a pressure responsive member movably mounted therein and subjected to the pressure therein. a second pressure responsive member carried by and movably mounted with respect to said iirst named pressure responsive member and subjected to the pressure of fiuid in said casing, said second named pressure responsive member having' an area larger than that of said rst named pressure responsive member, means for connecting one of said pressure responsive members directly with the device to be actuated, and resilient means associated with said pressure responsive members for opposingrelative movement of said members.

11. The combination with a source of ui pressure and a device to be actuated, oi' a Huid motor for actuating said device including a casa ing adapted to receive fluid pressure from the u source. a pressure responsive member mounted in the casing and subjected to the pressure therein and means for connecting said pressure responsive member with the device, a iiuid actuatnr for bodily` moving said iiuid motor including n. pressure responsive member of greater area than said first named pressure responsive member subjected at all times to the same pressure from the source as the first named pressure responsive member and means including a preloaded resilient element interposed between the casing and pressure responsive member oi' the iiuid motor for preventing actuation oi' the device thereby when the pressure supplied to the iiuid motor is less than a predetermined value.

WILLIAM J. ANDRES. ROY 8. SANFORD. 

